The Troubles: What led to Northern Ireland's conflict?
The conflict in Northern Ireland known as the Troubles lasted almost 30 years and cost the lives of more than 3,500 people.
In August 1969, the UK government sent troops to impose control.
But the origins of the Troubles date back to earlier than 1969, as BBC News NI's Jordan Kenny explains.
Watch more: Explore BBC archive film footage showing what led to the deployment of British troops in August 1969.